Question

which is radioactive?(helium/boron/redon/lead)​

Answer 1

Answer:

Explanation:

Helium

Answer 2

hi,

_______

$\bold{Radon}$

is the radioactive element.

Atomic Number of Radon is 86.

Extra:-

•Helium is a gas.

•Boron is a metal.

•Lead is a metal.